Os Supratrochleare Related Elbow Pain
Elbow pain secondary to os supratrochleare is being seen with increasing frequency in clinical practice owing to the increased interest in physical fitness and the use of exercise machines. Os supratrochleare is the name given to an accessory ossicle occasionally found in the posterior elbow.
This accessory ossicle often is found adjacent to the proximal aspect of the olecranon process. It is thought that accessory ossicles such as os supratrochleare bones serve to decrease the friction and pressure of tendons as they pass in proximity to a joint. Similar accessory ossicles are found in the feet, hands, and wrists.
Elbow pain secondary to os supratrochleare is characterized by tenderness and pain over the posterior elbow. Patients often describe a feeling of having gravel in their elbow and may report a grating sensation with flexion and extension of the elbow.
The pain of os supratrochleare worsens with activities that require repeated flexion and extension of the elbow or with forceful overhead throwing.
Os supratrochleare is often associated with loose bodies in the elbow joint and may coexist with olecranon bursitis.
What are the Symptoms
On physical examination, pain can be reproduced by pressure on the os supratrochleare. In contrast to olecranon bursitis, in which the tender area remains over the olecranon bursa, with os supratrochleare, the area of maximal tenderness is just above the olecranon process. A creaking or grating sensation may be appreciated by the examiner and locking or catching on extension and flexion of the elbow occasionally may be present.
How is Os Supratrochleare Related Elbow Pain diagnosed?
Plain radiographs are indicated in all patients with os supratrochleare to rule out fractures and identify accessory ossicles that may have become inflamed.
Plain radiographs also often identify loose bodies or joint mice frequently seen in patients with elbow pain secondary to os supratrochleare. Based on the patient’s clinical presentation, additional testing, including complete blood cell count, erythrocyte sedimentation rate, and antinuclear antibody testing, may be indicated.
Magnetic resonance imaging (MRI) and ultrasound imaging of the elbow joint is indicated if joint instability, occult mass, or tumor is suspected and to clarify the diagnosis further. Radionucleotide bone scanning may be useful in identifying stress fractures or tumors of the elbow and distal humerus that may be missed on plain radiographs.
Primary pathological processes of the elbow, including gout and occult fractures, may mimic the pain and disability associated with os supratrochleare. Entrapment neuropathies, such as ulnar tunnel syndrome, also may confuse the diagnosis, as may bursitis, tendinitis, and epicondylitis of the elbow, which may coexist with os supratrochleare.
Osteochondritis dissecans, Panner disease, and synovial chondromatosis also may mimic the pain associated with os supratrochleare. Primary and metastatic tumors of the elbow may manifest in a manner similar to elbow pain secondary to os supratrochleare.
Initial treatment of the pain and functional disability associated with os supratrochleare should include a combination of nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and physical therapy. The local application of heat and cold also may be beneficial. Avoidance of repetitive activities that aggravate the patient’s symptoms also may provide relief.
For patients who do not respond to these treatment modalities, injection of the os supratrochleare with a local anesthetic and steroid may be a reasonable next step. Ultrasound guidance may improve the accuracy of needle placement and decrease the incidence of needle-induced complications. For pain that persists, or if the os supratrochleare is causing damage to the elbow joint, surgical removal is indicated.
The major complication of injection of os supratrochleare is infection. This complication should be exceedingly rare if strict aseptic technique is followed.
Approximately 25% of patients report a transient increase in pain after injection of the os supratrochleare and should be warned of this possibility. Another potential risk of this injection technique is trauma to the extensor tendons from the injection itself.
Pain emanating from the elbow is a common problem encountered in clinical practice. Os supratrochleare must be distinguished from fractures of the elbow, fractures of the os supratrochleare itself, entrapment neuropathies of the ulnar nerve, bursitis, tendinitis, and epicondylitis.
Less common causes of posterior elbow pain are osteochondritis dissecans, Panner disease, and synovial chondromatosis.